Glow lamp



USC. i931. F SCHRTER 1,834,072

GLOW LAMP Filed June 26. 1929 Illllllllll INVENTQR rmz SCHROTER BY WMATTORNEY Patented* Dec. 1, 1931 UNITED STATES PATENT?` OFFICE FRITZSCHRTIB, 0F BERLIN', GERMANY, ASSIGNOB T0 TELEFUNKEN' GESELLSCHAFT FRIDRAHTLOSE TELF-RAIPHIE I. B. H., 0F BERLIN', GEBIANY, A CORPORATION OFGERMANY Grow LAMP Application filed .Tune 26, 1929, Seriallo. 873,744,and in Germanyluly '4, 1928.

' The present invention relates to glowdischarge lamps as adapted to thephotographic or visible recording of current variations, particularlyfor the purposes of optical telegraphy, picture telegraphy, television,producing sound records on moving picture films, and similar purposes.It is useful both in connection with glow-discharge lamps operating witha relatively cold cathode and a correspondingly high cathode fall as well as with lamps wherein the cathode fall'ls diminished by the use ofthermal emission, as in glow-discharge lamps furnished with a heatedcathode.

According to the prior art, glow-discharge lamps of this kind wereequipped witha'n anode and a cathode, but the A. C. passing therethroughwas used onlyin one direction, irrespective of whether the cathode glowor the positive luminous column served as the electrically controlledlight source.

The invention has been illustrated by the accompanying drawings,wherein: l Fig. 1 shows one of the circuit arrangements adapted to thispurpose and to the operation of such lamps, the latter being operatedmostly in connection with an amplifier; Y

Fig. 2 shows a preferred form of glow lamp construction; and,

Fig. 3 shows a circuit arrangement for util lizing the lamp shown byFig. 2.

Now, referring to Fig. 1 of the drawings, the glow-discharge lamp 1 isinserted in the circuit of a D. C. source, say, a battery 2, the currentbeing adjusted to a definite value by .the aid of resistance 3. By meansof transformer 4, the D. C. potential derived from 2 has superposedthereon acontrolling A. C.

potential whose amplitude and frequency is` indicated or recorded by thelight variations. Transformer 4f, for instance, is contained in theplate circuit of the last tube of anamplifier which ampliflestelegraphically received picture signals. Inasmuch as a D. C. potentialexists between the electrodes ofthe glow lamp 1 upon which thecontrolling" A. C. potential of 4 having comparatively low amplitude issu erposed, it will be seen that one half wave o the A. C. potentialwhich is of v A. C. potential will counteract the D. C. po-

tential so that the discharge current and the luminous intensity of thelamp are correspondingly diminished. Inasmuch as the value of thecurrent which flows in 4 when the A. C. potential is of zero value isusually,

set to such low amounts that it is not capable of producing practicallyany photographic action upon the film or not lcapable of resulting in aluminous impression or perception in television, it will be seen thatthe second half of the wave of A. C. potential, since it undergoes areduction both in the value of the current and luminous radiation, islost so far as the recording or visual impression is concerned. Anotheraggravating fact present under certain circumstances is that thepotential diiierence or minimum vcurrent required for maintaining thedischarge is not attained, with the result that the circuit may bebroken, and that the operation of the outfit becomes unstable.

Now, according to the present invention, a glow-dischargelamp of thekind before described, as shown in Fig. 2, is furnished with threeelectrodes, that is to say, either with two distinct anodes and a jointcathode, or else with two cathodes and a common anode. Which form ofconstruction should preferably be chosen depends upon whether it is thenegative glow layer at the cathode that is used as the luminous source,or whether other parts of the discharge, such as the 'positive column isemployed.- In what follows, a

- lamp is described by reference to Fig. 2 with a cold cathode and theutilization of a primary or secondary cathode' .glow la er.

sired, bein sealed by fusion in separate tubular appendages 7 and 8. Theshape of such anodes and seals does not fall inside the scope of thisinvention, and this holds true also of constructional details, theprovision of distinct diaphragms, screens, or the like, as used inconnection with the different uses and applications of the lamp. Whenthe discharge passes through the gas filling which, for lnstance, in thecase of -photography consists of a markedly actinic mixture of argon andnitrogen, or in the case of television of a mixture of neon and heliumexhibiting great brightness inside the visible spectral range, theinterior of cathode 5 is filled with a glow light, while at theconstricted outlet opening thereof, a secondaryy glow light of greatintensity is produced which is radiated off across a window 11 made fromglass, quartz, or other transparent material cemented thereon.

The arrangement hereinbefore described is capable of a great number ofmodifications as regards the nature of the cathode and the utilizedportion of the discharge, especially in cases where a common anode andtwo distinct cathodes are employed.

Now, a lamp of this kind allows of the utilization of both halves of thecontrolling A. C., and it thus insures a higher eiiciency; in otherwords, at the same amplifier power double photographic blackening ordouble luminosity.

A circuit arrangement useful for operating the scheme is shown by way ofexample in Fig. 3, though the same is capable of various modifications.The D. C. potential source 2 is again connected in series with aresistance 3- and' cathode 5, opposite which there are mounted the twoanodes' 9 and 10,

similarly as in Fig, 2,-'the latter being united with the two ends ofthe secondary winding of a transformer 12 to the middle of which theother pole of the D. C. source 2 is connected. 'I'he primary winding of12 is again connected in the output circuit of an amplifier. As will bereadily understood, the two half-waves of the controlling A. C.potential are so superimposed upon the discharge D. C. that an amplifiedor intensified current passes over to the cathode 5 alternately from theanode 9 and from the anode 10. As a result, both half-waves cause anintensified luminosity.

Other changes and modifications will at once suggest themselves to thoseskilled in the art to which the invention relates. and I, therefore.believe myself to be entitled to make and use all modifications of thisinvention such as fall fairly within the spirit and scope of thehereinafter appended claims. lI aving now described my invention, I caim 1. In a glow lamp construction, a cathode .5 member, a plurality ofanode members cooperating with said cathode member and spaced aparttherefrom, and a tubular memr surrounding said cathode member andextending outwardly therefrom toward said anode members.

2. A glow lamp construction adapted to produce luminous rays from bothhalves of supplied alternating currents com rising a pair of anodemembers arranged su stantially adjacent each other, a cathode memberremotely spaced and equi-distant from each of said anode members, and atubular insulating member surrounding said cathode and extending forsubstantially the distance separating the said anode members from saidcathode members for shielding said cathode member and confining the glowproduced within said lamp to a predetermined area.

3. In a glow lamp construction, a cathode member, a tubular insulatingmember surrounding said cathode member and extending outwardlytherefrom, said tubular member being open at the end thereof remote fromsaid cathode. a pair of anode members separated from said cathode memberand arranged adjacent the open end of said tubular member opposite saidcathode, and an enclosing envelope surrounding all of said electrodes.

4. In a glow lamp construction, a cathode member, a tubular insulatingmember surrounding said cathode member and extending outwardlytherefrom, a pair of anode members separated fromsaid cathode member andarranged at the end of said tubular member opposite said cathode, and anenclosing envelope surrounding all of said electrodes.

FRITZ SCHRTER.

